News reports and government warnings about eating seafood that contains high levels of mercury have frightened many consumers into avoiding certain fish species altogether and prompted some consumer advocates to warn against eating any seafood, What’s more, fishermen and seafood processors go nuts every time they hear another expert warn people away from seafood, because a dip in sales always follows the negative publicity.
But a researcher in North Dakota says the warnings are misplaced.
It’s not the excess of mercury, it’s the shortage of another element necessary for life that can cause the serious brain damage now associated with ingesting mercury.
“The data indicates it’s not a mercury toxicity, it’s a selenium deficiency,” said Dr. Nicholas Ralston, professor with the Energy and Environmental Research Center at the University of North Dakota. What’s more, said Ralston, research proved this 50 years ago, but somehow, the information was ignored or buried.
“Mercury can damage the brain severely, as illustrated in the 1970s in Iraq, where many people died after eating grain treated with a fungicide containing mercury. The grain was intended for planting, not human consumption, but the people were starving, so they ate it. They suffered free radical damage,” said Ralston. “There was oxidative damage all over their brains.” But that’s because they ingested high levels of mercury with no selenium.
In 2004, the Environmental Protection Agency and the Food and Drug
Administration issued a joint advisory warning women of childbearing age to avoid eating some species of fish altogether — shark, swordfish, tilefish and King mackerel. The advisory also warned the same women to eat no more than six oz. of canned, white Albacore tuna per week, while conversely recommending they eat 12 oz. of low-mercury fish per week for the health benefits. The advisory went on to recommend eating “light,” not “white” tuna because other species contain less mercury.
Americans on average eat only five ounces of fish per week, so the advisory actually recommends the targeted group consume more than double the amount of fish they currently eat. But after a similar advisory was issued by the FDA in 2001, a study indicated consumption of seafood among pregnant women in the U.S. dropped by 17 percent.
Members of the seafood industry, many scientists and doctors have argued all along that the health benefits of eating fish far outweigh the risks — without necessarily knowing about or certainly without mentioning the selenium-to-mercury ratio. Their arguments are now getting more than a boost from Ralston and a few other researchers.
“Selenium is essential for life, like oxygen and sulfur, but especially in the brain which needs protection from all kinds of free radicals. Selenium protection is vital. Free radicals destroy brain cells. Nature provides protection for the brain in selenium,” said Ralston, who will present his information in posters at a conference in Portland intended to identify issues around contaminants in fish. The 2007 EPA Fish Forum will be held July 23-26 at the Holiday Inn by the Bay.